<script>
  let cart = {
    277: {
      num: 7,
      checked: true
    },
    293: {
      num: 2,
      checked: false
    },
    57224: {
      num: 3,
      checked: true
    }
  }

  let _cart = {...cart}

  // 遍历cart,删除掉checked商品、
  for (let key in cart) {
    if (cart[key].checked) {
      delete cart[key]
    }
  }
  console.log(_cart)
</script>